1. Field of the Invention
The present invention relates to a keypad assembly, and in particular to a thin keypad assembly.
2. Description of Prior Art
With the continuous progress of communication technology, many electronic products tend to be made compact, thereby to reduce the size and weight thereof and facilitate a user to carry. In order to reduce the size and weight of the electronic product, the volume of the internal integrated circuit has to be reduced. In addition, the area and thickness of the keypad acting as an operational interface of the electronic product should be also reduced, so that it can be easily mounted in a communication device.
U.S. Pat. No. 7,070,349 B2, entitled “THIN KEYPAD AND COMPONENTS FOR ELECTRONICS DEVICES AND METHODS” and shown in FIG. 16, discloses a conventional keypad assembly, in which after the keypad is assembled, a seam B exists between the key layer A and key layer A on the keypad. Although the seam B will not affect the operation of neighboring keys, foreign matters (such as dust or fine particles) are easily filled into the seam, affecting the smoothness in pressing the keys. Alternatively, water may penetrate into the electronic product through the seam, causing the poor contact of the circuit board and the corrosion damage of the components.
Further, Taiwan Patent No. I252159, entitled “KEYPAD MODULE STRUCTURE AND THE METHOD FOR MAKING THE SAME” and shown in FIG. 17, emphasizes that the gap E (hollowed portion) between a displaying body C and a key body D is reduced to be less than 0.01 mm, thereby to increase the aesthetic appearance and tightness. Although the gap E between the displaying body C and the key body D is reduced, after a long-term use, foreign matters may be still filled therein. Even, water may penetrate into the electronic product through the gap, causing the poor contact of the circuit board and the corrosion damage of the components.